Daniel Kessler is a major character in Redhill. He is a corrupt and sadistic prison guard, and a suspect in a recent murder investigation. He is portrayed by Leo Gregory.
At some point in his career, Kessler had an affair with DI Bridges - who was married at the time - and it is heavily implied he is the biological father of her son. Kessler uses this to blackmail Bridges - she witnessed him brutally beating and killing a drug dealer, but because of her relationship with Kessler, she kept quite, claiming that she and Kessler found the dealer murdered.